drivers/net/tun.c

   1 /*
   2  *  TUN - Universal TUN/TAP device driver.
   3  *  Copyright (C) 1999-2002 Maxim Krasnyansky <[email protected]>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
  16  */
  17
  18 /*
  19  *  Changes:
  20  *
  21  *  Mike Kershaw <[email protected]> 2005/08/14
  22  *    Add TUNSETLINK ioctl to set the link encapsulation
  23  *
  24  *  Mark Smith <[email protected]>
  25  *    Use random_ether_addr() for tap MAC address.
  26  *
  27  *  Harald Roelle <[email protected]>  2004/04/20
  28  *    Fixes in packet dropping, queue length setting and queue wakeup.
  29  *    Increased default tx queue length.
  30  *    Added ethtool API.
  31  *    Minor cleanups
  32  *
  33  *  Daniel Podlejski <[email protected]>
  34  *    Modifications for 2.3.99-pre5 kernel.
  35  */
  36
  37 #define DRV_NAME        "tun"
  38 #define DRV_VERSION     "1.6"
  39 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  40 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <[email protected]>"
  41
  42 #include <linux/module.h>
  43 #include <linux/errno.h>
  44 #include <linux/kernel.h>
  45 #include <linux/major.h>
  46 #include <linux/slab.h>
  47 #include <linux/poll.h>
  48 #include <linux/fcntl.h>
  49 #include <linux/init.h>
  50 #include <linux/skbuff.h>
  51 #include <linux/netdevice.h>
  52 #include <linux/etherdevice.h>
  53 #include <linux/miscdevice.h>
  54 #include <linux/ethtool.h>
  55 #include <linux/rtnetlink.h>
  56 #include <linux/compat.h>
  57 #include <linux/if.h>
  58 #include <linux/if_arp.h>
  59 #include <linux/if_ether.h>
  60 #include <linux/if_tun.h>
  61 #include <linux/crc32.h>
  62 #include <linux/nsproxy.h>
  63 #include <linux/virtio_net.h>
  64 #include <linux/rcupdate.h>
  65 #include <net/net_namespace.h>
  66 #include <net/netns/generic.h>
  67 #include <net/rtnetlink.h>
  68 #include <net/sock.h>
  69
  70 #include <asm/system.h>
  71 #include <asm/uaccess.h>
  72
  73 /* Uncomment to enable debugging */
  74 /* #define TUN_DEBUG 1 */
  75
  76 #ifdef TUN_DEBUG
  77 static int debug;
  78
  79 #define DBG  if(tun->debug)printk
  80 #define DBG1 if(debug==2)printk
  81 #else
  82 #define DBG( a... )
  83 #define DBG1( a... )
  84 #endif
  85
  86 #define FLT_EXACT_COUNT 8
  87 struct tap_filter {
  88         unsigned int    count;    /* Number of addrs. Zero means disabled */
  89         u32             mask[2];  /* Mask of the hashed addrs */
  90         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
  91 };
  92
  93 struct tun_file {
  94         atomic_t count;
  95         struct tun_struct *tun;
  96         struct net *net;
  97 };
  98
  99 struct tun_sock;
 100
 101 struct tun_struct {
 102         struct tun_file         *tfile;
 103         unsigned int            flags;
 104         uid_t                   owner;
 105         gid_t                   group;
 106
 107         struct net_device       *dev;
 108         struct fasync_struct    *fasync;
 109
 110         struct tap_filter       txflt;
 111         struct socket           socket;
 112
 113 #ifdef TUN_DEBUG
 114         int debug;
 115 #endif
 116 };
 117
 118 struct tun_sock {
 119         struct sock             sk;
 120         struct tun_struct       *tun;
 121 };
 122
 123 static inline struct tun_sock *tun_sk(struct sock *sk)
 124 {
 125         return container_of(sk, struct tun_sock, sk);
 126 }
 127
 128 static int tun_attach(struct tun_struct *tun, struct file *file)
 129 {
 130         struct tun_file *tfile = file->private_data;
 131         int err;
 132
 133         ASSERT_RTNL();
 134
 135         netif_tx_lock_bh(tun->dev);
 136
 137         err = -EINVAL;
 138         if (tfile->tun)
 139                 goto out;
 140
 141         err = -EBUSY;
 142         if (tun->tfile)
 143                 goto out;
 144
 145         err = 0;
 146         tfile->tun = tun;
 147         tun->tfile = tfile;
 148         tun->socket.file = file;
 149         dev_hold(tun->dev);
 150         sock_hold(tun->socket.sk);
 151         atomic_inc(&tfile->count);
 152
 153 out:
 154         netif_tx_unlock_bh(tun->dev);
 155         return err;
 156 }
 157
 158 static void __tun_detach(struct tun_struct *tun)
 159 {
 160         /* Detach from net device */
 161         netif_tx_lock_bh(tun->dev);
 162         tun->tfile = NULL;
 163         tun->socket.file = NULL;
 164         netif_tx_unlock_bh(tun->dev);
 165
 166         /* Drop read queue */
 167         skb_queue_purge(&tun->socket.sk->sk_receive_queue);
 168
 169         /* Drop the extra count on the net device */
 170         dev_put(tun->dev);
 171 }
 172
 173 static void tun_detach(struct tun_struct *tun)
 174 {
 175         rtnl_lock();
 176         __tun_detach(tun);
 177         rtnl_unlock();
 178 }
 179
 180 static struct tun_struct *__tun_get(struct tun_file *tfile)
 181 {
 182         struct tun_struct *tun = NULL;
 183
 184         if (atomic_inc_not_zero(&tfile->count))
 185                 tun = tfile->tun;
 186
 187         return tun;
 188 }
 189
 190 static struct tun_struct *tun_get(struct file *file)
 191 {
 192         return __tun_get(file->private_data);
 193 }
 194
 195 static void tun_put(struct tun_struct *tun)
 196 {
 197         struct tun_file *tfile = tun->tfile;
 198
 199         if (atomic_dec_and_test(&tfile->count))
 200                 tun_detach(tfile->tun);
 201 }
 202
 203 /* TAP filterting */
 204 static void addr_hash_set(u32 *mask, const u8 *addr)
 205 {
 206         int n = ether_crc(ETH_ALEN, addr) >> 26;
 207         mask[n >> 5] |= (1 << (n & 31));
 208 }
 209
 210 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 211 {
 212         int n = ether_crc(ETH_ALEN, addr) >> 26;
 213         return mask[n >> 5] & (1 << (n & 31));
 214 }
 215
 216 static int update_filter(struct tap_filter *filter, void __user *arg)
 217 {
 218         struct { u8 u[ETH_ALEN]; } *addr;
 219         struct tun_filter uf;
 220         int err, alen, n, nexact;
 221
 222         if (copy_from_user(&uf, arg, sizeof(uf)))
 223                 return -EFAULT;
 224
 225         if (!uf.count) {
 226                 /* Disabled */
 227                 filter->count = 0;
 228                 return 0;
 229         }
 230
 231         alen = ETH_ALEN * uf.count;
 232         addr = kmalloc(alen, GFP_KERNEL);
 233         if (!addr)
 234                 return -ENOMEM;
 235
 236         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 237                 err = -EFAULT;
 238                 goto done;
 239         }
 240
 241         /* The filter is updated without holding any locks. Which is
 242          * perfectly safe. We disable it first and in the worst
 243          * case we'll accept a few undesired packets. */
 244         filter->count = 0;
 245         wmb();
 246
 247         /* Use first set of addresses as an exact filter */
 248         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 249                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 250
 251         nexact = n;
 252
 253         /* Remaining multicast addresses are hashed,
 254          * unicast will leave the filter disabled. */
 255         memset(filter->mask, 0, sizeof(filter->mask));
 256         for (; n < uf.count; n++) {
 257                 if (!is_multicast_ether_addr(addr[n].u)) {
 258                         err = 0; /* no filter */
 259                         goto done;
 260                 }
 261                 addr_hash_set(filter->mask, addr[n].u);
 262         }
 263
 264         /* For ALLMULTI just set the mask to all ones.
 265          * This overrides the mask populated above. */
 266         if ((uf.flags & TUN_FLT_ALLMULTI))
 267                 memset(filter->mask, ~0, sizeof(filter->mask));
 268
 269         /* Now enable the filter */
 270         wmb();
 271         filter->count = nexact;
 272
 273         /* Return the number of exact filters */
 274         err = nexact;
 275
 276 done:
 277         kfree(addr);
 278         return err;
 279 }
 280
 281 /* Returns: 0 - drop, !=0 - accept */
 282 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 283 {
 284         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 285          * at this point. */
 286         struct ethhdr *eh = (struct ethhdr *) skb->data;
 287         int i;
 288
 289         /* Exact match */
 290         for (i = 0; i < filter->count; i++)
 291                 if (!compare_ether_addr(eh->h_dest, filter->addr[i]))
 292                         return 1;
 293
 294         /* Inexact match (multicast only) */
 295         if (is_multicast_ether_addr(eh->h_dest))
 296                 return addr_hash_test(filter->mask, eh->h_dest);
 297
 298         return 0;
 299 }
 300
 301 /*
 302  * Checks whether the packet is accepted or not.
 303  * Returns: 0 - drop, !=0 - accept
 304  */
 305 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 306 {
 307         if (!filter->count)
 308                 return 1;
 309
 310         return run_filter(filter, skb);
 311 }
 312
 313 /* Network device part of the driver */
 314
 315 static const struct ethtool_ops tun_ethtool_ops;
 316
 317 /* Net device detach from fd. */
 318 static void tun_net_uninit(struct net_device *dev)
 319 {
 320         struct tun_struct *tun = netdev_priv(dev);
 321         struct tun_file *tfile = tun->tfile;
 322
 323         /* Inform the methods they need to stop using the dev.
 324          */
 325         if (tfile) {
 326                 wake_up_all(&tun->socket.wait);
 327                 if (atomic_dec_and_test(&tfile->count))
 328                         __tun_detach(tun);
 329         }
 330 }
 331
 332 static void tun_free_netdev(struct net_device *dev)
 333 {
 334         struct tun_struct *tun = netdev_priv(dev);
 335
 336         sock_put(tun->socket.sk);
 337 }
 338
 339 /* Net device open. */
 340 static int tun_net_open(struct net_device *dev)
 341 {
 342         netif_start_queue(dev);
 343         return 0;
 344 }
 345
 346 /* Net device close. */
 347 static int tun_net_close(struct net_device *dev)
 348 {
 349         netif_stop_queue(dev);
 350         return 0;
 351 }
 352
 353 /* Net device start xmit */
 354 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 355 {
 356         struct tun_struct *tun = netdev_priv(dev);
 357
 358         DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
 359
 360         /* Drop packet if interface is not attached */
 361         if (!tun->tfile)
 362                 goto drop;
 363
 364         /* Drop if the filter does not like it.
 365          * This is a noop if the filter is disabled.
 366          * Filter can be enabled only for the TAP devices. */
 367         if (!check_filter(&tun->txflt, skb))
 368                 goto drop;
 369
 370         if (tun->socket.sk->sk_filter &&
 371             sk_filter(tun->socket.sk, skb))
 372                 goto drop;
 373
 374         if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) {
 375                 if (!(tun->flags & TUN_ONE_QUEUE)) {
 376                         /* Normal queueing mode. */
 377                         /* Packet scheduler handles dropping of further packets. */
 378                         netif_stop_queue(dev);
 379
 380                         /* We won't see all dropped packets individually, so overrun
 381                          * error is more appropriate. */
 382                         dev->stats.tx_fifo_errors++;
 383                 } else {
 384                         /* Single queue mode.
 385                          * Driver handles dropping of all packets itself. */
 386                         goto drop;
 387                 }
 388         }
 389
 390         /* Orphan the skb - required as we might hang on to it
 391          * for indefinite time. */
 392         skb_orphan(skb);
 393
 394         /* Enqueue packet */
 395         skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb);
 396         dev->trans_start = jiffies;
 397
 398         /* Notify and wake up reader process */
 399         if (tun->flags & TUN_FASYNC)
 400                 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
 401         wake_up_interruptible_poll(&tun->socket.wait, POLLIN |
 402                                    POLLRDNORM | POLLRDBAND);
 403         return NETDEV_TX_OK;
 404
 405 drop:
 406         dev->stats.tx_dropped++;
 407         kfree_skb(skb);
 408         return NETDEV_TX_OK;
 409 }
 410
 411 static void tun_net_mclist(struct net_device *dev)
 412 {
 413         /*
 414          * This callback is supposed to deal with mc filter in
 415          * _rx_ path and has nothing to do with the _tx_ path.
 416          * In rx path we always accept everything userspace gives us.
 417          */
 418         return;
 419 }
 420
 421 #define MIN_MTU 68
 422 #define MAX_MTU 65535
 423
 424 static int
 425 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 426 {
 427         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 428                 return -EINVAL;
 429         dev->mtu = new_mtu;
 430         return 0;
 431 }
 432
 433 static const struct net_device_ops tun_netdev_ops = {
 434         .ndo_uninit             = tun_net_uninit,
 435         .ndo_open               = tun_net_open,
 436         .ndo_stop               = tun_net_close,
 437         .ndo_start_xmit         = tun_net_xmit,
 438         .ndo_change_mtu         = tun_net_change_mtu,
 439 };
 440
 441 static const struct net_device_ops tap_netdev_ops = {
 442         .ndo_uninit             = tun_net_uninit,
 443         .ndo_open               = tun_net_open,
 444         .ndo_stop               = tun_net_close,
 445         .ndo_start_xmit         = tun_net_xmit,
 446         .ndo_change_mtu         = tun_net_change_mtu,
 447         .ndo_set_multicast_list = tun_net_mclist,
 448         .ndo_set_mac_address    = eth_mac_addr,
 449         .ndo_validate_addr      = eth_validate_addr,
 450 };
 451
 452 /* Initialize net device. */
 453 static void tun_net_init(struct net_device *dev)
 454 {
 455         struct tun_struct *tun = netdev_priv(dev);
 456
 457         switch (tun->flags & TUN_TYPE_MASK) {
 458         case TUN_TUN_DEV:
 459                 dev->netdev_ops = &tun_netdev_ops;
 460
 461                 /* Point-to-Point TUN Device */
 462                 dev->hard_header_len = 0;
 463                 dev->addr_len = 0;
 464                 dev->mtu = 1500;
 465
 466                 /* Zero header length */
 467                 dev->type = ARPHRD_NONE;
 468                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 469                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 470                 break;
 471
 472         case TUN_TAP_DEV:
 473                 dev->netdev_ops = &tap_netdev_ops;
 474                 /* Ethernet TAP Device */
 475                 ether_setup(dev);
 476
 477                 random_ether_addr(dev->dev_addr);
 478
 479                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 480                 break;
 481         }
 482 }
 483
 484 /* Character device part */
 485
 486 /* Poll */
 487 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 488 {
 489         struct tun_file *tfile = file->private_data;
 490         struct tun_struct *tun = __tun_get(tfile);
 491         struct sock *sk;
 492         unsigned int mask = 0;
 493
 494         if (!tun)
 495                 return POLLERR;
 496
 497         sk = tun->socket.sk;
 498
 499         DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
 500
 501         poll_wait(file, &tun->socket.wait, wait);
 502
 503         if (!skb_queue_empty(&sk->sk_receive_queue))
 504                 mask |= POLLIN | POLLRDNORM;
 505
 506         if (sock_writeable(sk) ||
 507             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 508              sock_writeable(sk)))
 509                 mask |= POLLOUT | POLLWRNORM;
 510
 511         if (tun->dev->reg_state != NETREG_REGISTERED)
 512                 mask = POLLERR;
 513
 514         tun_put(tun);
 515         return mask;
 516 }
 517
 518 /* prepad is the amount to reserve at front.  len is length after that.
 519  * linear is a hint as to how much to copy (usually headers). */
 520 static inline struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
 521                                             size_t prepad, size_t len,
 522                                             size_t linear, int noblock)
 523 {
 524         struct sock *sk = tun->socket.sk;
 525         struct sk_buff *skb;
 526         int err;
 527
 528         /* Under a page?  Don't bother with paged skb. */
 529         if (prepad + len < PAGE_SIZE || !linear)
 530                 linear = len;
 531
 532         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 533                                    &err);
 534         if (!skb)
 535                 return ERR_PTR(err);
 536
 537         skb_reserve(skb, prepad);
 538         skb_put(skb, linear);
 539         skb->data_len = len - linear;
 540         skb->len += len - linear;
 541
 542         return skb;
 543 }
 544
 545 /* Get packet from user space buffer */
 546 static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
 547                                        const struct iovec *iv, size_t count,
 548                                        int noblock)
 549 {
 550         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
 551         struct sk_buff *skb;
 552         size_t len = count, align = 0;
 553         struct virtio_net_hdr gso = { 0 };
 554         int offset = 0;
 555
 556         if (!(tun->flags & TUN_NO_PI)) {
 557                 if ((len -= sizeof(pi)) > count)
 558                         return -EINVAL;
 559
 560                 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
 561                         return -EFAULT;
 562                 offset += sizeof(pi);
 563         }
 564
 565         if (tun->flags & TUN_VNET_HDR) {
 566                 if ((len -= sizeof(gso)) > count)
 567                         return -EINVAL;
 568
 569                 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
 570                         return -EFAULT;
 571
 572                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
 573                     gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
 574                         gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
 575
 576                 if (gso.hdr_len > len)
 577                         return -EINVAL;
 578                 offset += sizeof(gso);
 579         }
 580
 581         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 582                 align = NET_IP_ALIGN;
 583                 if (unlikely(len < ETH_HLEN ||
 584                              (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
 585                         return -EINVAL;
 586         }
 587
 588         skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock);
 589         if (IS_ERR(skb)) {
 590                 if (PTR_ERR(skb) != -EAGAIN)
 591                         tun->dev->stats.rx_dropped++;
 592                 return PTR_ERR(skb);
 593         }
 594
 595         if (skb_copy_datagram_from_iovec(skb, 0, iv, offset, len)) {
 596                 tun->dev->stats.rx_dropped++;
 597                 kfree_skb(skb);
 598                 return -EFAULT;
 599         }
 600
 601         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 602                 if (!skb_partial_csum_set(skb, gso.csum_start,
 603                                           gso.csum_offset)) {
 604                         tun->dev->stats.rx_frame_errors++;
 605                         kfree_skb(skb);
 606                         return -EINVAL;
 607                 }
 608         } else if (tun->flags & TUN_NOCHECKSUM)
 609                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 610
 611         switch (tun->flags & TUN_TYPE_MASK) {
 612         case TUN_TUN_DEV:
 613                 if (tun->flags & TUN_NO_PI) {
 614                         switch (skb->data[0] & 0xf0) {
 615                         case 0x40:
 616                                 pi.proto = htons(ETH_P_IP);
 617                                 break;
 618                         case 0x60:
 619                                 pi.proto = htons(ETH_P_IPV6);
 620                                 break;
 621                         default:
 622                                 tun->dev->stats.rx_dropped++;
 623                                 kfree_skb(skb);
 624                                 return -EINVAL;
 625                         }
 626                 }
 627
 628                 skb_reset_mac_header(skb);
 629                 skb->protocol = pi.proto;
 630                 skb->dev = tun->dev;
 631                 break;
 632         case TUN_TAP_DEV:
 633                 skb->protocol = eth_type_trans(skb, tun->dev);
 634                 break;
 635         };
 636
 637         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 638                 pr_debug("GSO!\n");
 639                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 640                 case VIRTIO_NET_HDR_GSO_TCPV4:
 641                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 642                         break;
 643                 case VIRTIO_NET_HDR_GSO_TCPV6:
 644                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 645                         break;
 646                 case VIRTIO_NET_HDR_GSO_UDP:
 647                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 648                         break;
 649                 default:
 650                         tun->dev->stats.rx_frame_errors++;
 651                         kfree_skb(skb);
 652                         return -EINVAL;
 653                 }
 654
 655                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 656                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 657
 658                 skb_shinfo(skb)->gso_size = gso.gso_size;
 659                 if (skb_shinfo(skb)->gso_size == 0) {
 660                         tun->dev->stats.rx_frame_errors++;
 661                         kfree_skb(skb);
 662                         return -EINVAL;
 663                 }
 664
 665                 /* Header must be checked, and gso_segs computed. */
 666                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 667                 skb_shinfo(skb)->gso_segs = 0;
 668         }
 669
 670         netif_rx_ni(skb);
 671
 672         tun->dev->stats.rx_packets++;
 673         tun->dev->stats.rx_bytes += len;
 674
 675         return count;
 676 }
 677
 678 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 679                               unsigned long count, loff_t pos)
 680 {
 681         struct file *file = iocb->ki_filp;
 682         struct tun_struct *tun = tun_get(file);
 683         ssize_t result;
 684
 685         if (!tun)
 686                 return -EBADFD;
 687
 688         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 689
 690         result = tun_get_user(tun, iv, iov_length(iv, count),
 691                               file->f_flags & O_NONBLOCK);
 692
 693         tun_put(tun);
 694         return result;
 695 }
 696
 697 /* Put packet to the user space buffer */
 698 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 699                                        struct sk_buff *skb,
 700                                        const struct iovec *iv, int len)
 701 {
 702         struct tun_pi pi = { 0, skb->protocol };
 703         ssize_t total = 0;
 704
 705         if (!(tun->flags & TUN_NO_PI)) {
 706                 if ((len -= sizeof(pi)) < 0)
 707                         return -EINVAL;
 708
 709                 if (len < skb->len) {
 710                         /* Packet will be striped */
 711                         pi.flags |= TUN_PKT_STRIP;
 712                 }
 713
 714                 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
 715                         return -EFAULT;
 716                 total += sizeof(pi);
 717         }
 718
 719         if (tun->flags & TUN_VNET_HDR) {
 720                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
 721                 if ((len -= sizeof(gso)) < 0)
 722                         return -EINVAL;
 723
 724                 if (skb_is_gso(skb)) {
 725                         struct skb_shared_info *sinfo = skb_shinfo(skb);
 726
 727                         /* This is a hint as to how much should be linear. */
 728                         gso.hdr_len = skb_headlen(skb);
 729                         gso.gso_size = sinfo->gso_size;
 730                         if (sinfo->gso_type & SKB_GSO_TCPV4)
 731                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 732                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
 733                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 734                         else if (sinfo->gso_type & SKB_GSO_UDP)
 735                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 736                         else
 737                                 BUG();
 738                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 739                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 740                 } else
 741                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 742
 743                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 744                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 745                         gso.csum_start = skb->csum_start - skb_headroom(skb);
 746                         gso.csum_offset = skb->csum_offset;
 747                 } /* else everything is zero */
 748
 749                 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
 750                                                sizeof(gso))))
 751                         return -EFAULT;
 752                 total += sizeof(gso);
 753         }
 754
 755         len = min_t(int, skb->len, len);
 756
 757         skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
 758         total += skb->len;
 759
 760         tun->dev->stats.tx_packets++;
 761         tun->dev->stats.tx_bytes += len;
 762
 763         return total;
 764 }
 765
 766 static ssize_t tun_do_read(struct tun_struct *tun,
 767                            struct kiocb *iocb, const struct iovec *iv,
 768                            ssize_t len, int noblock)
 769 {
 770         DECLARE_WAITQUEUE(wait, current);
 771         struct sk_buff *skb;
 772         ssize_t ret = 0;
 773
 774         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 775
 776         add_wait_queue(&tun->socket.wait, &wait);
 777         while (len) {
 778                 current->state = TASK_INTERRUPTIBLE;
 779
 780                 /* Read frames from the queue */
 781                 if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
 782                         if (noblock) {
 783                                 ret = -EAGAIN;
 784                                 break;
 785                         }
 786                         if (signal_pending(current)) {
 787                                 ret = -ERESTARTSYS;
 788                                 break;
 789                         }
 790                         if (tun->dev->reg_state != NETREG_REGISTERED) {
 791                                 ret = -EIO;
 792                                 break;
 793                         }
 794
 795                         /* Nothing to read, let's sleep */
 796                         schedule();
 797                         continue;
 798                 }
 799                 netif_wake_queue(tun->dev);
 800
 801                 ret = tun_put_user(tun, skb, iv, len);
 802                 kfree_skb(skb);
 803                 break;
 804         }
 805
 806         current->state = TASK_RUNNING;
 807         remove_wait_queue(&tun->socket.wait, &wait);
 808
 809         return ret;
 810 }
 811
 812 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 813                             unsigned long count, loff_t pos)
 814 {
 815         struct file *file = iocb->ki_filp;
 816         struct tun_file *tfile = file->private_data;
 817         struct tun_struct *tun = __tun_get(tfile);
 818         ssize_t len, ret;
 819
 820         if (!tun)
 821                 return -EBADFD;
 822         len = iov_length(iv, count);
 823         if (len < 0) {
 824                 ret = -EINVAL;
 825                 goto out;
 826         }
 827
 828         ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
 829         ret = min_t(ssize_t, ret, len);
 830 out:
 831         tun_put(tun);
 832         return ret;
 833 }
 834
 835 static void tun_setup(struct net_device *dev)
 836 {
 837         struct tun_struct *tun = netdev_priv(dev);
 838
 839         tun->owner = -1;
 840         tun->group = -1;
 841
 842         dev->ethtool_ops = &tun_ethtool_ops;
 843         dev->destructor = tun_free_netdev;
 844 }
 845
 846 /* Trivial set of netlink ops to allow deleting tun or tap
 847  * device with netlink.
 848  */
 849 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
 850 {
 851         return -EINVAL;
 852 }
 853
 854 static struct rtnl_link_ops tun_link_ops __read_mostly = {
 855         .kind           = DRV_NAME,
 856         .priv_size      = sizeof(struct tun_struct),
 857         .setup          = tun_setup,
 858         .validate       = tun_validate,
 859 };
 860
 861 static void tun_sock_write_space(struct sock *sk)
 862 {
 863         struct tun_struct *tun;
 864
 865         if (!sock_writeable(sk))
 866                 return;
 867
 868         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
 869                 return;
 870
 871         if (sk_sleep(sk) && waitqueue_active(sk_sleep(sk)))
 872                 wake_up_interruptible_sync_poll(sk_sleep(sk), POLLOUT |
 873                                                 POLLWRNORM | POLLWRBAND);
 874
 875         tun = tun_sk(sk)->tun;
 876         kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
 877 }
 878
 879 static void tun_sock_destruct(struct sock *sk)
 880 {
 881         free_netdev(tun_sk(sk)->tun->dev);
 882 }
 883
 884 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
 885                        struct msghdr *m, size_t total_len)
 886 {
 887         struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
 888         return tun_get_user(tun, m->msg_iov, total_len,
 889                             m->msg_flags & MSG_DONTWAIT);
 890 }
 891
 892 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
 893                        struct msghdr *m, size_t total_len,
 894                        int flags)
 895 {
 896         struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
 897         int ret;
 898         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
 899                 return -EINVAL;
 900         ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
 901                           flags & MSG_DONTWAIT);
 902         if (ret > total_len) {
 903                 m->msg_flags |= MSG_TRUNC;
 904                 ret = flags & MSG_TRUNC ? ret : total_len;
 905         }
 906         return ret;
 907 }
 908
 909 /* Ops structure to mimic raw sockets with tun */
 910 static const struct proto_ops tun_socket_ops = {
 911         .sendmsg = tun_sendmsg,
 912         .recvmsg = tun_recvmsg,
 913 };
 914
 915 static struct proto tun_proto = {
 916         .name           = "tun",
 917         .owner          = THIS_MODULE,
 918         .obj_size       = sizeof(struct tun_sock),
 919 };
 920
 921 static int tun_flags(struct tun_struct *tun)
 922 {
 923         int flags = 0;
 924
 925         if (tun->flags & TUN_TUN_DEV)
 926                 flags |= IFF_TUN;
 927         else
 928                 flags |= IFF_TAP;
 929
 930         if (tun->flags & TUN_NO_PI)
 931                 flags |= IFF_NO_PI;
 932
 933         if (tun->flags & TUN_ONE_QUEUE)
 934                 flags |= IFF_ONE_QUEUE;
 935
 936         if (tun->flags & TUN_VNET_HDR)
 937                 flags |= IFF_VNET_HDR;
 938
 939         return flags;
 940 }
 941
 942 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
 943                               char *buf)
 944 {
 945         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 946         return sprintf(buf, "0x%x\n", tun_flags(tun));
 947 }
 948
 949 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
 950                               char *buf)
 951 {
 952         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 953         return sprintf(buf, "%d\n", tun->owner);
 954 }
 955
 956 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
 957                               char *buf)
 958 {
 959         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 960         return sprintf(buf, "%d\n", tun->group);
 961 }
 962
 963 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
 964 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
 965 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
 966
 967 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 968 {
 969         struct sock *sk;
 970         struct tun_struct *tun;
 971         struct net_device *dev;
 972         int err;
 973
 974         dev = __dev_get_by_name(net, ifr->ifr_name);
 975         if (dev) {
 976                 const struct cred *cred = current_cred();
 977
 978                 if (ifr->ifr_flags & IFF_TUN_EXCL)
 979                         return -EBUSY;
 980                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
 981                         tun = netdev_priv(dev);
 982                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
 983                         tun = netdev_priv(dev);
 984                 else
 985                         return -EINVAL;
 986
 987                 if (((tun->owner != -1 && cred->euid != tun->owner) ||
 988                      (tun->group != -1 && !in_egroup_p(tun->group))) &&
 989                     !capable(CAP_NET_ADMIN))
 990                         return -EPERM;
 991                 err = security_tun_dev_attach(tun->socket.sk);
 992                 if (err < 0)
 993                         return err;
 994
 995                 err = tun_attach(tun, file);
 996                 if (err < 0)
 997                         return err;
 998         }
 999         else {
1000                 char *name;
1001                 unsigned long flags = 0;
1002
1003                 if (!capable(CAP_NET_ADMIN))
1004                         return -EPERM;
1005                 err = security_tun_dev_create();
1006                 if (err < 0)
1007                         return err;
1008
1009                 /* Set dev type */
1010                 if (ifr->ifr_flags & IFF_TUN) {
1011                         /* TUN device */
1012                         flags |= TUN_TUN_DEV;
1013                         name = "tun%d";
1014                 } else if (ifr->ifr_flags & IFF_TAP) {
1015                         /* TAP device */
1016                         flags |= TUN_TAP_DEV;
1017                         name = "tap%d";
1018                 } else
1019                         return -EINVAL;
1020
1021                 if (*ifr->ifr_name)
1022                         name = ifr->ifr_name;
1023
1024                 dev = alloc_netdev(sizeof(struct tun_struct), name,
1025                                    tun_setup);
1026                 if (!dev)
1027                         return -ENOMEM;
1028
1029                 dev_net_set(dev, net);
1030                 dev->rtnl_link_ops = &tun_link_ops;
1031
1032                 tun = netdev_priv(dev);
1033                 tun->dev = dev;
1034                 tun->flags = flags;
1035                 tun->txflt.count = 0;
1036
1037                 err = -ENOMEM;
1038                 sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
1039                 if (!sk)
1040                         goto err_free_dev;
1041
1042                 init_waitqueue_head(&tun->socket.wait);
1043                 tun->socket.ops = &tun_socket_ops;
1044                 sock_init_data(&tun->socket, sk);
1045                 sk->sk_write_space = tun_sock_write_space;
1046                 sk->sk_sndbuf = INT_MAX;
1047
1048                 tun_sk(sk)->tun = tun;
1049
1050                 security_tun_dev_post_create(sk);
1051
1052                 tun_net_init(dev);
1053
1054                 if (strchr(dev->name, '%')) {
1055                         err = dev_alloc_name(dev, dev->name);
1056                         if (err < 0)
1057                                 goto err_free_sk;
1058                 }
1059
1060                 err = register_netdevice(tun->dev);
1061                 if (err < 0)
1062                         goto err_free_sk;
1063
1064                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1065                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1066                     device_create_file(&tun->dev->dev, &dev_attr_group))
1067                         printk(KERN_ERR "Failed to create tun sysfs files\n");
1068
1069                 sk->sk_destruct = tun_sock_destruct;
1070
1071                 err = tun_attach(tun, file);
1072                 if (err < 0)
1073                         goto failed;
1074         }
1075
1076         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
1077
1078         if (ifr->ifr_flags & IFF_NO_PI)
1079                 tun->flags |= TUN_NO_PI;
1080         else
1081                 tun->flags &= ~TUN_NO_PI;
1082
1083         if (ifr->ifr_flags & IFF_ONE_QUEUE)
1084                 tun->flags |= TUN_ONE_QUEUE;
1085         else
1086                 tun->flags &= ~TUN_ONE_QUEUE;
1087
1088         if (ifr->ifr_flags & IFF_VNET_HDR)
1089                 tun->flags |= TUN_VNET_HDR;
1090         else
1091                 tun->flags &= ~TUN_VNET_HDR;
1092
1093         /* Make sure persistent devices do not get stuck in
1094          * xoff state.
1095          */
1096         if (netif_running(tun->dev))
1097                 netif_wake_queue(tun->dev);
1098
1099         strcpy(ifr->ifr_name, tun->dev->name);
1100         return 0;
1101
1102  err_free_sk:
1103         sock_put(sk);
1104  err_free_dev:
1105         free_netdev(dev);
1106  failed:
1107         return err;
1108 }
1109
1110 static int tun_get_iff(struct net *net, struct tun_struct *tun,
1111                        struct ifreq *ifr)
1112 {
1113         DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
1114
1115         strcpy(ifr->ifr_name, tun->dev->name);
1116
1117         ifr->ifr_flags = tun_flags(tun);
1118
1119         return 0;
1120 }
1121
1122 /* This is like a cut-down ethtool ops, except done via tun fd so no
1123  * privs required. */
1124 static int set_offload(struct net_device *dev, unsigned long arg)
1125 {
1126         unsigned int old_features, features;
1127
1128         old_features = dev->features;
1129         /* Unset features, set them as we chew on the arg. */
1130         features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
1131                                     |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6
1132                                     |NETIF_F_UFO));
1133
1134         if (arg & TUN_F_CSUM) {
1135                 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1136                 arg &= ~TUN_F_CSUM;
1137
1138                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1139                         if (arg & TUN_F_TSO_ECN) {
1140                                 features |= NETIF_F_TSO_ECN;
1141                                 arg &= ~TUN_F_TSO_ECN;
1142                         }
1143                         if (arg & TUN_F_TSO4)
1144                                 features |= NETIF_F_TSO;
1145                         if (arg & TUN_F_TSO6)
1146                                 features |= NETIF_F_TSO6;
1147                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1148                 }
1149
1150                 if (arg & TUN_F_UFO) {
1151                         features |= NETIF_F_UFO;
1152                         arg &= ~TUN_F_UFO;
1153                 }
1154         }
1155
1156         /* This gives the user a way to test for new features in future by
1157          * trying to set them. */
1158         if (arg)
1159                 return -EINVAL;
1160
1161         dev->features = features;
1162         if (old_features != dev->features)
1163                 netdev_features_change(dev);
1164
1165         return 0;
1166 }
1167
1168 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1169                             unsigned long arg, int ifreq_len)
1170 {
1171         struct tun_file *tfile = file->private_data;
1172         struct tun_struct *tun;
1173         void __user* argp = (void __user*)arg;
1174         struct sock_fprog fprog;
1175         struct ifreq ifr;
1176         int sndbuf;
1177         int ret;
1178
1179         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
1180                 if (copy_from_user(&ifr, argp, ifreq_len))
1181                         return -EFAULT;
1182
1183         if (cmd == TUNGETFEATURES) {
1184                 /* Currently this just means: "what IFF flags are valid?".
1185                  * This is needed because we never checked for invalid flags on
1186                  * TUNSETIFF. */
1187                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1188                                 IFF_VNET_HDR,
1189                                 (unsigned int __user*)argp);
1190         }
1191
1192         rtnl_lock();
1193
1194         tun = __tun_get(tfile);
1195         if (cmd == TUNSETIFF && !tun) {
1196                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1197
1198                 ret = tun_set_iff(tfile->net, file, &ifr);
1199
1200                 if (ret)
1201                         goto unlock;
1202
1203                 if (copy_to_user(argp, &ifr, ifreq_len))
1204                         ret = -EFAULT;
1205                 goto unlock;
1206         }
1207
1208         ret = -EBADFD;
1209         if (!tun)
1210                 goto unlock;
1211
1212         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
1213
1214         ret = 0;
1215         switch (cmd) {
1216         case TUNGETIFF:
1217                 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1218                 if (ret)
1219                         break;
1220
1221                 if (copy_to_user(argp, &ifr, ifreq_len))
1222                         ret = -EFAULT;
1223                 break;
1224
1225         case TUNSETNOCSUM:
1226                 /* Disable/Enable checksum */
1227                 if (arg)
1228                         tun->flags |= TUN_NOCHECKSUM;
1229                 else
1230                         tun->flags &= ~TUN_NOCHECKSUM;
1231
1232                 DBG(KERN_INFO "%s: checksum %s\n",
1233                     tun->dev->name, arg ? "disabled" : "enabled");
1234                 break;
1235
1236         case TUNSETPERSIST:
1237                 /* Disable/Enable persist mode */
1238                 if (arg)
1239                         tun->flags |= TUN_PERSIST;
1240                 else
1241                         tun->flags &= ~TUN_PERSIST;
1242
1243                 DBG(KERN_INFO "%s: persist %s\n",
1244                     tun->dev->name, arg ? "enabled" : "disabled");
1245                 break;
1246
1247         case TUNSETOWNER:
1248                 /* Set owner of the device */
1249                 tun->owner = (uid_t) arg;
1250
1251                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
1252                 break;
1253
1254         case TUNSETGROUP:
1255                 /* Set group of the device */
1256                 tun->group= (gid_t) arg;
1257
1258                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
1259                 break;
1260
1261         case TUNSETLINK:
1262                 /* Only allow setting the type when the interface is down */
1263                 if (tun->dev->flags & IFF_UP) {
1264                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
1265                                 tun->dev->name);
1266                         ret = -EBUSY;
1267                 } else {
1268                         tun->dev->type = (int) arg;
1269                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
1270                         ret = 0;
1271                 }
1272                 break;
1273
1274 #ifdef TUN_DEBUG
1275         case TUNSETDEBUG:
1276                 tun->debug = arg;
1277                 break;
1278 #endif
1279         case TUNSETOFFLOAD:
1280                 ret = set_offload(tun->dev, arg);
1281                 break;
1282
1283         case TUNSETTXFILTER:
1284                 /* Can be set only for TAPs */
1285                 ret = -EINVAL;
1286                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1287                         break;
1288                 ret = update_filter(&tun->txflt, (void __user *)arg);
1289                 break;
1290
1291         case SIOCGIFHWADDR:
1292                 /* Get hw addres */
1293                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1294                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1295                 if (copy_to_user(argp, &ifr, ifreq_len))
1296                         ret = -EFAULT;
1297                 break;
1298
1299         case SIOCSIFHWADDR:
1300                 /* Set hw address */
1301                 DBG(KERN_DEBUG "%s: set hw address: %pM\n",
1302                         tun->dev->name, ifr.ifr_hwaddr.sa_data);
1303
1304                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1305                 break;
1306
1307         case TUNGETSNDBUF:
1308                 sndbuf = tun->socket.sk->sk_sndbuf;
1309                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1310                         ret = -EFAULT;
1311                 break;
1312
1313         case TUNSETSNDBUF:
1314                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1315                         ret = -EFAULT;
1316                         break;
1317                 }
1318
1319                 tun->socket.sk->sk_sndbuf = sndbuf;
1320                 break;
1321
1322         case TUNATTACHFILTER:
1323                 /* Can be set only for TAPs */
1324                 ret = -EINVAL;
1325                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1326                         break;
1327                 ret = -EFAULT;
1328                 if (copy_from_user(&fprog, argp, sizeof(fprog)))
1329                         break;
1330
1331                 ret = sk_attach_filter(&fprog, tun->socket.sk);
1332                 break;
1333
1334         case TUNDETACHFILTER:
1335                 /* Can be set only for TAPs */
1336                 ret = -EINVAL;
1337                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1338                         break;
1339                 ret = sk_detach_filter(tun->socket.sk);
1340                 break;
1341
1342         default:
1343                 ret = -EINVAL;
1344                 break;
1345         };
1346
1347 unlock:
1348         rtnl_unlock();
1349         if (tun)
1350                 tun_put(tun);
1351         return ret;
1352 }
1353
1354 static long tun_chr_ioctl(struct file *file,
1355                           unsigned int cmd, unsigned long arg)
1356 {
1357         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
1358 }
1359
1360 #ifdef CONFIG_COMPAT
1361 static long tun_chr_compat_ioctl(struct file *file,
1362                          unsigned int cmd, unsigned long arg)
1363 {
1364         switch (cmd) {
1365         case TUNSETIFF:
1366         case TUNGETIFF:
1367         case TUNSETTXFILTER:
1368         case TUNGETSNDBUF:
1369         case TUNSETSNDBUF:
1370         case SIOCGIFHWADDR:
1371         case SIOCSIFHWADDR:
1372                 arg = (unsigned long)compat_ptr(arg);
1373                 break;
1374         default:
1375                 arg = (compat_ulong_t)arg;
1376                 break;
1377         }
1378
1379         /*
1380          * compat_ifreq is shorter than ifreq, so we must not access beyond
1381          * the end of that structure. All fields that are used in this
1382          * driver are compatible though, we don't need to convert the
1383          * contents.
1384          */
1385         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
1386 }
1387 #endif /* CONFIG_COMPAT */
1388
1389 static int tun_chr_fasync(int fd, struct file *file, int on)
1390 {
1391         struct tun_struct *tun = tun_get(file);
1392         int ret;
1393
1394         if (!tun)
1395                 return -EBADFD;
1396
1397         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
1398
1399         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1400                 goto out;
1401
1402         if (on) {
1403                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1404                 if (ret)
1405                         goto out;
1406                 tun->flags |= TUN_FASYNC;
1407         } else
1408                 tun->flags &= ~TUN_FASYNC;
1409         ret = 0;
1410 out:
1411         tun_put(tun);
1412         return ret;
1413 }
1414
1415 static int tun_chr_open(struct inode *inode, struct file * file)
1416 {
1417         struct tun_file *tfile;
1418
1419         DBG1(KERN_INFO "tunX: tun_chr_open\n");
1420
1421         tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1422         if (!tfile)
1423                 return -ENOMEM;
1424         atomic_set(&tfile->count, 0);
1425         tfile->tun = NULL;
1426         tfile->net = get_net(current->nsproxy->net_ns);
1427         file->private_data = tfile;
1428         return 0;
1429 }
1430
1431 static int tun_chr_close(struct inode *inode, struct file *file)
1432 {
1433         struct tun_file *tfile = file->private_data;
1434         struct tun_struct *tun;
1435
1436         tun = __tun_get(tfile);
1437         if (tun) {
1438                 struct net_device *dev = tun->dev;
1439
1440                 DBG(KERN_INFO "%s: tun_chr_close\n", dev->name);
1441
1442                 __tun_detach(tun);
1443
1444                 /* If desirable, unregister the netdevice. */
1445                 if (!(tun->flags & TUN_PERSIST)) {
1446                         rtnl_lock();
1447                         if (dev->reg_state == NETREG_REGISTERED)
1448                                 unregister_netdevice(dev);
1449                         rtnl_unlock();
1450                 }
1451         }
1452
1453         tun = tfile->tun;
1454         if (tun)
1455                 sock_put(tun->socket.sk);
1456
1457         put_net(tfile->net);
1458         kfree(tfile);
1459
1460         return 0;
1461 }
1462
1463 static const struct file_operations tun_fops = {
1464         .owner  = THIS_MODULE,
1465         .llseek = no_llseek,
1466         .read  = do_sync_read,
1467         .aio_read  = tun_chr_aio_read,
1468         .write = do_sync_write,
1469         .aio_write = tun_chr_aio_write,
1470         .poll   = tun_chr_poll,
1471         .unlocked_ioctl = tun_chr_ioctl,
1472 #ifdef CONFIG_COMPAT
1473         .compat_ioctl = tun_chr_compat_ioctl,
1474 #endif
1475         .open   = tun_chr_open,
1476         .release = tun_chr_close,
1477         .fasync = tun_chr_fasync
1478 };
1479
1480 static struct miscdevice tun_miscdev = {
1481         .minor = TUN_MINOR,
1482         .name = "tun",
1483         .nodename = "net/tun",
1484         .fops = &tun_fops,
1485 };
1486
1487 /* ethtool interface */
1488
1489 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1490 {
1491         cmd->supported          = 0;
1492         cmd->advertising        = 0;
1493         cmd->speed              = SPEED_10;
1494         cmd->duplex             = DUPLEX_FULL;
1495         cmd->port               = PORT_TP;
1496         cmd->phy_address        = 0;
1497         cmd->transceiver        = XCVR_INTERNAL;
1498         cmd->autoneg            = AUTONEG_DISABLE;
1499         cmd->maxtxpkt           = 0;
1500         cmd->maxrxpkt           = 0;
1501         return 0;
1502 }
1503
1504 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1505 {
1506         struct tun_struct *tun = netdev_priv(dev);
1507
1508         strcpy(info->driver, DRV_NAME);
1509         strcpy(info->version, DRV_VERSION);
1510         strcpy(info->fw_version, "N/A");
1511
1512         switch (tun->flags & TUN_TYPE_MASK) {
1513         case TUN_TUN_DEV:
1514                 strcpy(info->bus_info, "tun");
1515                 break;
1516         case TUN_TAP_DEV:
1517                 strcpy(info->bus_info, "tap");
1518                 break;
1519         }
1520 }
1521
1522 static u32 tun_get_msglevel(struct net_device *dev)
1523 {
1524 #ifdef TUN_DEBUG
1525         struct tun_struct *tun = netdev_priv(dev);
1526         return tun->debug;
1527 #else
1528         return -EOPNOTSUPP;
1529 #endif
1530 }
1531
1532 static void tun_set_msglevel(struct net_device *dev, u32 value)
1533 {
1534 #ifdef TUN_DEBUG
1535         struct tun_struct *tun = netdev_priv(dev);
1536         tun->debug = value;
1537 #endif
1538 }
1539
1540 static u32 tun_get_link(struct net_device *dev)
1541 {
1542         struct tun_struct *tun = netdev_priv(dev);
1543         return !!tun->tfile;
1544 }
1545
1546 static u32 tun_get_rx_csum(struct net_device *dev)
1547 {
1548         struct tun_struct *tun = netdev_priv(dev);
1549         return (tun->flags & TUN_NOCHECKSUM) == 0;
1550 }
1551
1552 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1553 {
1554         struct tun_struct *tun = netdev_priv(dev);
1555         if (data)
1556                 tun->flags &= ~TUN_NOCHECKSUM;
1557         else
1558                 tun->flags |= TUN_NOCHECKSUM;
1559         return 0;
1560 }
1561
1562 static const struct ethtool_ops tun_ethtool_ops = {
1563         .get_settings   = tun_get_settings,
1564         .get_drvinfo    = tun_get_drvinfo,
1565         .get_msglevel   = tun_get_msglevel,
1566         .set_msglevel   = tun_set_msglevel,
1567         .get_link       = tun_get_link,
1568         .get_rx_csum    = tun_get_rx_csum,
1569         .set_rx_csum    = tun_set_rx_csum
1570 };
1571
1572
1573 static int __init tun_init(void)
1574 {
1575         int ret = 0;
1576
1577         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1578         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1579
1580         ret = rtnl_link_register(&tun_link_ops);
1581         if (ret) {
1582                 printk(KERN_ERR "tun: Can't register link_ops\n");
1583                 goto err_linkops;
1584         }
1585
1586         ret = misc_register(&tun_miscdev);
1587         if (ret) {
1588                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1589                 goto err_misc;
1590         }
1591         return  0;
1592 err_misc:
1593         rtnl_link_unregister(&tun_link_ops);
1594 err_linkops:
1595         return ret;
1596 }
1597
1598 static void tun_cleanup(void)
1599 {
1600         misc_deregister(&tun_miscdev);
1601         rtnl_link_unregister(&tun_link_ops);
1602 }
1603
1604 /* Get an underlying socket object from tun file.  Returns error unless file is
1605  * attached to a device.  The returned object works like a packet socket, it
1606  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
1607  * holding a reference to the file for as long as the socket is in use. */
1608 struct socket *tun_get_socket(struct file *file)
1609 {
1610         struct tun_struct *tun;
1611         if (file->f_op != &tun_fops)
1612                 return ERR_PTR(-EINVAL);
1613         tun = tun_get(file);
1614         if (!tun)
1615                 return ERR_PTR(-EBADFD);
1616         tun_put(tun);
1617         return &tun->socket;
1618 }
1619 EXPORT_SYMBOL_GPL(tun_get_socket);
1620
1621 module_init(tun_init);
1622 module_exit(tun_cleanup);
1623 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1624 MODULE_AUTHOR(DRV_COPYRIGHT);
1625 MODULE_LICENSE("GPL");
1626 MODULE_ALIAS_MISCDEV(TUN_MINOR);